The invention relates to a process for the continuous chipping of timbers of different length and shape, in particular of round timbers, which are piled essentially in longitudinal alignment one on top of the other and side by side in an at least approximately grain-parallel arrangement and are thus advanced in cycles. The timbers are compiled into a long timber pack of specific cross section, in the longitudinal direction, are cross-cut after each advancement cycle by a pack length corresponding to the advancement distance and corresponding, at the same time, to the usable chipping length to form, in each case, equal-length short timber packs. The timbers are subjected on both sides of the sawing plane to perpendicular compression forces, the short timber packs thus formed being conveyed forward in continuous succession transversely to their grain alignment, being therein supported, at least on their underside and the two end sides, and eventually being chipped parallel to the grain.
The invention further relates to a device for the continuous chipping of timbers of different length and shape, the device having a timber feed channel for receiving the timbers which are piled essentially in longitudinal alignment one on top of the other and side by side in an at least approximately grain-parallel arrangement and thus compiled into a long timber pack of specific cross section. The device includes advancement elements for the cyclical advancement of this long timber pack past a cut-off device; pressure mechanisms, disposed on both sides of the sawing plane and exerting perpendicular compression forces upon the long timber pack; and a chipping conveyor, the width of which corresponds to the length of the short timber pack or to the usable length of a chipping tool. The device supports the short timber packs, at least on their underside and their two end sides, and, transversely to their grain direction, feeds the chipping tool for grain-parallel chipping.
German Auslegeschrift 2 135 930 describes a process and a device for chipping waste timber of different length and diameter. According to this document, the pieces of timber are piled essentially in longitudinal alignment one on top of the other and side by side in an at least approximately grain-parallel arrangement and are thus compiled into a specific cross-sectional unit. The pieces of timber are next advanced in cycles in the longitudinal direction and, af ter each advancement cycle, cross-cut by a part-length corresponding to the distance of advancement. The sawn-off short timber pack is compressed, approximately vertically to its longitudinal alignment, into a block which, following the conclusion of the pressing operation, is fed to the chipping machine in continuous succession to the preceding short timber pack and transversely to its longitudinal alignment.
The previously known plant operates as follows: the pieces of timber of different length, thickness and shape, made up of waste timber, are laid side by side and one on top of the other into the timber supply channel, such that their cross section is essentially filled. The long timber pack which is thus formed is advanced in cycles and hence pushed past the cut-off device, which can be conf igured as a band saw, chain saw or circular saw, or even indeed as hydraulically-actuated shearing tools. In this case, there is sawn off from the advanced long timber pack a short timber pack, the length of which corresponds to the working length of a block chipper cutter connected downstream. In the cross-cutting procedure, the timber is already vre-compressed, by means of a prepress, in its spatial arrangement one to the other, and is secured during the cross-cutting procedure. This sawn-off short timber pack is then compressed, in a press chamber connected downstream of the cut-off device and aligned with the timber feed channel, by a press ram to the extent that a cohesive, compact block is produced from approximately grain-parallel waste pieces. This block is then pushed by means of a pushing ram into a chipper shaft and hence into the "effective" range of conveyor chains which circulate there. The block, due to its heavy precompression, is intended not to fall apart. In the chipper shaft, the block thus follows straight on from the preceding block, so that a compact column of timber is produced which, under the influence of a continuously operating chain advancement, is advanced constantly towards the cutter block of the chipper and is evenly chipped.
If, in the case of this previously known plant, the cut-off block is not to fall apart on its further transportation, very high compression forces must be applied. In this case, the specific weight of the timber is increased and its grain structure at least partially destroyed. For round timbers, a device of this type is therefore unsuitable.
In the case of the previously known plant, it is another disadvantage that, following the cutting operation, the block located in the press chamber first has to be pushed out of the press chamber bef ore a further advancement cycle of the long timber pack can be effected. The recovery of the kicker arm entails a corresponding time loss. It is a further disadvantage that, in the cyclical advancement of the long timber pack, small timber sections or butt end slices which are lying in front of the forward-traveling long timber are able to come to rest transversely or, indeed, tilt forward. The filling volume in the press chamber is thereby reduced. A plurality of residual pieces are ground more or less vertically to the grain instead of being chipped parallel to the grain, as a result of which the energy requirement and the share of unwanted fine material are considerably increased.